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Brushless motor

a brushless motor and motor shaft technology, applied in the direction of rotating magnets, synchronous machines with stationary armatures, electrical apparatus, etc., can solve the problems of motor efficiency tending to decrease, and achieve the effect of limiting components costs and losses in assembly work efficiency, and high reliability of index signals

Inactive Publication Date: 2015-03-05
TOKYO PARTS IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a brushless motor that produces a highly reliable index signal while limiting component cost increases and losses in assembly work efficiency. The motor uses magnetic flux from the circumferential centers of the magnetic poles, which reduces the impact of changes in ambient temperature and magnetic disturbances. This allows the motor to be made with less precision in its dimensions and relative positioning between the indexing pole part and the magnetic flux detector, reducing costs and assembly work losses.

Problems solved by technology

Furthermore, in the brushless motor described in Japanese Patent Laid-Open Publication No. 2001-339889, because a window is provided in the rotor yoke and a portion of the drive magnet protrudes radially outward from this window, the motor efficiency tends to decrease if this window is overly large.

Method used

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Embodiment Construction

[0013]Hereafter, modes of embodiment of the present invention are described in detail with reference to the drawings. Note that the aspects and technical features of the present invention are not limited to those described hereafter, and are to be understood based on the descriptions throughout the specification and in the drawings, or based on the inventive ideas that can be grasped by the skilled artisan on the basis of these descriptions.

[0014]A brushless motor according to one mode of embodiment of the present invention will be described using FIG. 1 and FIG. 2. This exemplary brushless motor is an outer-rotor type brushless motor wherein the rotor rotates at the radial exterior of a stator, and principally comprises a mounting board 10, a bearing unit 20, a stator unit 30 and a rotor unit 40.

[0015]The mounting board 10 is constituted by a so-called iron substrate, on the surface of which a printed circuit is formed, or is constituted by a substrate wherein a printed circuit boa...

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Abstract

A rotor type brushless motor comprises a drive magnet having an indexing pole part that extends on one axial side thereof. This indexing pole part is formed at least in the range from the circumferential center of one north pole to the circumferential center of one adjacent south pole, and over no greater than the range from one circumferential end of the one north pole to the other circumferential end of the one south pole. A magnetic flux detector is arranged at a position axially facing the indexing pole part.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to an outer-rotor type brushless motor provided with an index detection mechanism.[0002]Outer-rotor type brushless motors are used as spindle motors for rotationally driving color wheels in projectors, polygon mirrors in printers and the like. Brushless motors of this sort are known in which an index detection mechanism is provided, which outputs a position signal of one pulse for each rotation (index signal) so as to detect the rotational position of the rotor.[0003]For example, in the brushless motor described in Japanese Patent Laid-Open Publication No. 2001-339889, windows are provided at multiple locations on a rotor yoke, and protrusions are provided on a portion of a ring-shaped drive magnet that fits in the inner periphery of the rotor yoke, which protrude radially outward through the windows. Here, one of these protrusions is provided at a position that straddles a north and south pole of the drive magnet, and a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H02K11/00
CPCH02K11/0021H02K29/08H02K21/22H02K2213/03H02K1/2791H02K11/215
Inventor TUCHIYA, MASAHISA
Owner TOKYO PARTS IND CO LTD